Distributor of mixes consisting of agglomerated ceramic or stone material for filling a mold

ABSTRACT

A mix distributor ( 10 ) for filling a tray-like mold ( 100 ) comprises a fixed structure ( 120 ), having a distribution surface ( 124 ) supporting a mold ( 100 ), and a movable housing ( 130 ), displaceable above the mold ( 100 ). The movable housing is provided with a hopper containing the mix having at its bottom end a port ( 150 ) for discharging the mix.  
     An extractor belt ( 160 ) which is integral with and positioned underneath the hopper ( 40; 140 ), forming the bottom thereof, is able to receive and convey the discharged mix ( 110 ) so that it falls by effect of gravity into the mold ( 100 ) and is uniformly distributed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Application PCT/EP2003/011990 filed on Oct. 29, 2003, now International Publication Number WO 2004/039547 published on May 13, 2004 and claims priority from Italian Patent Application TV2002A000131 filed on Oct. 31, 2002, the contents of which are herein wholly incorporated by reference.

DESCRIPTION

The present invention relates to a mix distributor for filling a mold having a substantially constant thickness with a mix of agglomerated ceramic or stone material.

The mix is formed by a mixture of granular material consisting of either natural or artificial hard stone or baked clay, which has a given grain size and the quantities of which are metered in a controlled manner, and by either an organic binder, chosen from among synthetic resins, or an inorganic binder, for example of the cement-based type.

These mix distributors are used for the manufacture of articles, particularly in the form of slabs, in plants consisting of a mix preparation station which is fed with the components forming the mix and in which mixing of the granular stone or ceramic material and the chosen binder is performed. The mix is transferred to a distributor which has the function of pouring and distributing the mix inside the molds which are filled uniformly.

Examples of mix distributors known in the art are disclosed by the patents FR-A-864 846, FR-A-1 591 141, FR-A-2 052 704, DD-A-294 453, U.S. Pat. No. 4,321,028.

The mix normally has the consistency of a wet sand, which tends to pack together in lumps, particularly when the binder consists of a viscous or sticky resin. The mold containing the mix is transferred to a station where the mix is compacted, for example by means of a simultaneous pressing and vibrating action in a vacuum environment (as described in the patent IT-A-1,056,388). Subsequently, the mix is transferred to a catalysis station when the binder is resinous or to a hardening station when the binder is of the inorganic type. Finally, the hardened slab is extracted from the mold and transferred to the subsequent processing steps such as sizing and smoothing/polishing.

In the patent U.S. Pat. No. 5,338,179 filed by the present Applicant an example of a distributor according to the known art, particularly suitable for sticky resin-based mixes, is described which comprises a fixed housing supporting the mold which must be uniformly filled with the mix of agglomerate material delivered by the said distributor.

The fixed housing has, mounted thereon, a movable housing equipped with a motor means so as to be displaceable above the mold such that the mix can be poured and distributed over the entire surface of the mold. The movable housing is provided with a hopper movable in the vertical direction and containing the mix of stone material and having at the bottom end a port for discharging the mix. The hopper is also equipped internally with a rotating shaft having blades which push and accompany the mix towards the discharge port so as to facilitate distribution of the mix inside the mold.

The mix distributed inside the mold forms a layer, the thickness of which is equal to the distance between the port for discharging the material from the hopper and the bottom of the mold. The distributor in question is therefore of the volumetric type since, by suitably adjusting the vertical position of the hopper, the thickness of the layer of mix and therefore of the resultant slab is varied.

In particular, a liquid or powder dye may be added onto the upper surface of the mix, before reaches the distributor, by means of a dye dispenser such as described in Italian patent No. 1 273 903 filed in the name of the present Applicant.

The aim is that of obtaining an end product with colored effects similar to those of natural stone and in particular of creating veined effects or tones which imitate as far as possible those which are typical of natural stone.

The dye is distributed over the surface of the mix in a discontinuous and irregular manner and in a predefined and metered quantity. The dye is basically “sprinkled” over the surface of the mix and then partially mixed with the remainder of the mix, without, however, altering the substantially localized distribution of dye with respect to the surface of the mix layer, which is a necessary condition for creating a final product with veined effects.

The mix distributor described in the mentioned Italian patent, although it is able to produce finished slabs with particular colored and veined effects, nevertheless poses technology-related problems.

In fact, whereas the mix distributor is displaced in order to pour the mix uniformly into the mold, the shaft equipped with blades stirs the mix so that, even if at the beginning the dye has the desired irregular and localized distribution necessary for creating the veined effects in the final slab, as distribution proceeds, the mix contained inside the hopper is mixed up by the shaft with blades and in this way homogenization of the mix occurs. The result is that the slab does not have the same appearance and therefore visual effect over the whole of its surface, but in the part of the slab in which the mix was last distributed the aesthetic properties vary and differ from the desired aesthetic effect.

The object of the present invention is therefore that of solving in an industrially advantageous manner the problems mentioned above with reference to the known art and particularly of providing a distributor with a simple construction which leads to the production of slabs, the aesthetic properties of which are optimum and uniform over their whole surface.

Moreover, the distributor must be able to be easily adjusted upon variation of the characteristics—such as the shape and thickness—of the layer of mix to be poured inside the mold and to allow an easy metering of the quantity of mix to be introduced into the hopper in order to form a slab with the required thickness and dimensions.

Last but not least, the distributor must function in such a way as to ensure that the mix is able to flow out easily and with a uniform thickness, even in the case of mixes having different physical properties, such as grain size, viscosity, etc.

The object is achieved with a distributor of the above discussed type, namely a mix distributor for filling a tray-like mold having a substantially constant thickness with the features of the appended claims.

In the case of manufacture of slabs with a veined effect, where a liquid or powder dye is distributed in a discontinuous manner, in zones or patches, onto the surface of the mix upstream of said hopper means, since the mix supplied by the hopper means is deposited on the conveyor means without being mixed, the deposited mix remains unaltered during the whole of the mold filling operation. The result is that the slabs have the same aesthetic properties over the whole of their surface.

Essentially the irregular and localized deposition of the dye in the mix does not vary during the various mix distribution stages, thereby enabling the formation of slabs with a veined effect which remains unchanged over the whole of their surface.

Moreover, the hopper means are equipped with intercepting means positioned in front of the mix discharge port and able to regulate the degree of opening of said port. Alternatively or additionally the conveyor means are provided with variable-speed motor means and/or motor means of the variable-speed type are used to displace said movable housing.

In this way, by simply varying respectively the degree of opening of the mix discharge port and/or the speed of advance of the conveyor means and/or the speed of displacement of the container means it is possible to vary the quantity of mix to be poured into the mold and therefore the thickness of the mix layer.

The distributor also comprises load sensors able to weigh the hopper means together with the mix contained therein so as to determine with extreme ease the quantity of mix which is strictly necessary for filling the mold and in particular to control on continuous basis the throughput of the material poured from the distributor into the mold during its displacement.

These and further advantageous features of the present invention will emerge more clearly from the following detailed description provided by way of a non-limiting example with reference to the accompanying drawing in which:

FIG. 1 is a schematic longitudinal view of a distributor according to the present invention;

FIG. 2 is a front view of the distributor shown in FIG. 1, with some details omitted for a better clarity;

FIG. 3 is a top plan view of the same distributor where, for the sake of simplicity, some of the parts shown in the preceding figures have been omitted;

FIG. 4 is a more detailed longitudinal view of the same distributor;

FIG. 5 is another front view showing the details omitted in FIG. 2;

FIG. 6 shows a variant of the part enclosed in the circle indicated by a dot-dash line in FIG. 4.

In the enclosed figures, 10 denotes overall a mix distributor for filling a tray-like mold, 100 which is usually made of rubber and has a substantially constant thickness, with a mix 110 of agglomerate stone or ceramic material.

The distributor 10 comprises a fixed structure 120 including pillars 122 and a support surface 124 preferably consisting of a conveyor belt for allowing movement of the mold 100 positioned on top of it. A frame or border 102 for temporarily containing the mix is inserted inside the mold 100 before commencing filling. The frame 102 is connected to actuating cylinders 126 which are mounted on the fixed housing 120. The containing frame 102 has a height greater than that of the adjacent perimetral edge of the mold 100 so as to prevent the fresh and therefore soft mix from flowing over the said edge when it is poured into the mold with a thickness greater than the final thickness. Preferably, as shown in FIGS. 1 and 2, the frame 102 has walls inclined towards the inside of the mold so as to prevent spillage of the mix when the frame 102 is removed.

A movable housing 130 is arranged above the distribution surface 124, being displaceable parallel to said surface 124, above the mold 100, by means of sliding guides (not shown). The movable housing 130 is also provided with a variable-speed motor 134 which allows its speed of displacement to be varied.

The movable housing 130 supports, above it, a hopper for containing the mix of agglomerate material, formed by four side walls lined with an anti-adhesive material and having an upper mouth 143 through which the fresh mix is fed. The hopper consists of a fixed external structure (not shown) and an internal structure 140 which, by means of handles (also not shown), may be extracted from the structure and replaced with a structure having a different size depending on the size of the slab of agglomerated ceramic or stone material to be produced in the mold 100. The internal structure 140 of the hopper has a flat vertical rear wall 141 and a front wall 142 which has at its bottom end a discharge port 150 of the mix. According to a main feature of the present invention the front wall 142 has a profile in which the upper portion 142A is inclined towards the rear wall 141 and the lower portion 142B begins at the minimum distance from the rear wall and ends at said discharge port 150. The geometry of this profile may be varied, and consequently optimized, depending on the physical characteristics (grain size, viscosity, etc.) of the mix. FIGS. 4 and 6 show, exclusively by way of example, two of the possible profiles 142′ and 142″ of said front wall 142 of the hopper internal structure 140. As indicated by the double pointed arrow C in FIGS. 1 and 4, either the whole internal structure 140 of the hopper or at least its front wall thereof 142 is vertically adjustable in order to vary the cross-section of the discharge port 150.

An extractor belt 160, driven by a variable-speed motor 162, able to receive the mix from the hopper 140 and forming the bottom thereof, is positioned underneath the hopper and integral with the movable housing 130. The top surface of the extractor belt 160, on which is deposited the mix flowing out from the internal structure 140 of the hopper through the discharge port 150, forms the bottom of the hopper and is inclined forwards, namely towards the discharge port 150 in the same manner as the lower portion 142B of the front wall 142 of the hopper internal structure 140. The mentioned inclination derives from the fact that the driving roller 164 of the extractor belt 160 needs to have a given diameter to ensure a sufficiently strong pull while the idle roller (not visible in the drawing) has a much smaller diameter to ensure an optimum fall down of the mix 110. In this manner the invention provides that the mix flow:

-   -   is substantially vertical and with a narrowing cross-section in         the upper region of the hopper, namely in front of the upper         portion 142A of the front wall 142 of the internal structure         140, and     -   becomes parallel to said top surface of the extractor belt 160         in the lower region of the hopper, namely in front of the lower         portion 142B of the front wall 142 of the internal structure         140.

Thanks to such profile of the front wall 142 of the internal structure 140, there is no accumulation of undischarged mix on the port 150, thus the thickness and the density of mix 110 flowing out from the said port are uniform. As a consequence the mix 110 is no longer poured in form of “spots” but as a continues layer in the mold 100.

The conveyor belt 160 is provided with a controlled-speed and adjustable motor 162, so that it is possible to vary the speed of discharge of the mix and therefore the throughput of the mix which is poured into the mold 100.

The mix 110 coming out of the hopper through the discharge port 150 is conveyed at a controlled speed to the free end 160A of the extractor belt 160, where the mix falls by means of gravity and is uniformly distributed inside the mold 100. A guide chute 168 is provided at the free end 160A of the conveyor belt 160, said chute—as shown in FIG. 2—extending transversely over practically the whole width of the mold 100 so as to favor the distribution of the mix therein.

The movable housing 130 is mounted on supports 164 provided with load sensors so as to monitor the weight of the mix 110 deposited on the extractor belt 160 and therefore to control the throughput of the mix poured into the mold 100, with the possibility of adjusting it by varying the speed of the belt 160 and/or the speed of displacement of the movable housing 130.

As shown in FIG. 5—in front of the discharge port 150 there is a comb or rake-like device 170 provided with a connecting rod and crank mechanism 174 which imparts to said device an alternating movement in a vertical plane parallel to the cross section of the discharge port 150, as indicated by the arrow D. In this way the teeth 172 of the device 170 break up any lumps which form in the mix 110 before the latter falls into the mold 100, so that the layer of mix inside the mold 100 is even more uniform;

A scraper device 180—see FIG. 5—is present at a given radial distance from the already mentioned idle roller of the extractor belt 160, said scraper device being characterized by a blade which, at the end of filling of the mold 100, scrapes off any residual amount of mix 110 supplied by the present distributor remaining attached to the extractor belt 160.

On the opposite side of the internal structure 140 of the hopper, there is also a cylindrical brush 185 having a horizontal axis—see FIG. 4—which is actuated by an associated motor (not shown) and which completes the work of the scraper device 180 for a carefully cleaning of the extractor belt 160.

The operating principle of the distributor is now described. In its starting position the hopper is filled with a quantity of mix slightly greater than that which is required to form a slab. Owing to the load sensors and since the weight when empty (tare) of the movable housing 130 is known, the hopper can be loaded with the desired quantity of mix (for example the quantity required for forming a slab).

The movable housing 130, together with the hopper and therefore also the extractor belt 160, is initially positioned at one end of the fixed housing 120 so that the mix 110 is poured starting from one end of the mold 100.

In order to commence filling of the mold 100, the motor 162 is energized in order to advance the extractor belt 160, then also the motor 134 is energized in order to displace the movable housing 130. The advancing movement—indicated by arrow A—of the extractor belt 160 and therefore the mix deposited thereon occurs in the same direction as the displacement of the movable housing 130—indicated by the arrow B, see FIG. 4.

The mix flows out of the discharge port 150 and at the end 160A of the extractor belt 160 falls inside the mold 100, being guided by the 1 chute 68. The displacement of the movable housing 30 continues so as to pour the mix 110 inside the whole length of the mold 100.

It should be noted that the mix may be poured into the mold 100 either during the outward travel movement only or may be poured, if necessary, both during the outward and the return travel movement, thereby allowing a reinforcing element of the end product, such as for example a meshwork, to be inserted between the two layers of mix.

It should be noted that the thickness of the mix poured into the mold 100 depends on the rate of discharge of the mix from the extractor belt 160 (which is controlled continuously by the computer which manages the load sensors) and may be modified very easily in three different ways:

-   -   1. by adjusting the height of the discharge port 150 through a         vertical displacement of at least the front wall 142 of the         hopper internal structure 140;     -   2. by adjusting the speed of displacement of the movable housing         130;     -   3. by adjusting the speed of advancing movement of the extractor         belt 160.

By reducing the height of the discharge port 150 or by increasing the speed of displacement of the movable housing 130 or by slowing down the speed of advancing movement of the extractor belt 160, the thickness of the layer of mix 110 poured into the mold 100 decreases. Conversely, by increasing the height of the discharge port 50 or by slowing down the speed of displacement of the movable housing 130 or by increasing the speed of advancing movement of the extractor belt 160, the thickness of the layer of mix 110 poured into the mold 100 increases.

In view of the ease of performing filling of the hopper with the desired quantity of mix, for example that required for forming a slab, due to the use of the load sensors, and in view of the precision and immediacy of the adjustments necessary for pouring into the mold 100 a layer of mix 110 of a predefined thickness in one or more passes, without the mix being remixed as it passes from the hopper to the mold 100, a slab with optimum aesthetic properties which are constant over the whole of its surface is always obtained. Equally evident is the simplicity in construction of the device and the extreme ease with which it may be cleaned in order to allow use of a different colored mix.

Finally it is clear that the scope of protection of the following claims also includes any further modifications or changes which are functionally or conceptually equivalent to that claimed below. 

1. Distributor for filling a tray-like mold (100) with a mix (110) of agglomerated ceramic or stone material having a substantially constant thickness, comprising: a—a fixed structure (120) including a distribution surface (124), where said mold (100) is movably supported, b—a movable housing (130) driven by motor means (134) so as to be displaced above said mold (100) while the mix (110) is distributed over the whole surface thereof, c—hopper means supported by said movable housing (130) and provided at its bottom end with a port (150) for discharging the mix (110), d—conveyor means integral with said movable housing (130), positioned underneath said hopper means and forming the bottom thereof, which comprise an extractor belt (160) able to receive on its top surface said mix (110) which passes through said discharge port (150) and to convey the mix to its free end (1 60A) so that the mix falls by effect of gravity and is uniformly poured inside said mold (100), characterized in that e—said hopper means have a structure (140) comprising a first flat and vertical wall (141) and a second wall (142), opposite to said first wall (141), defining at its bottom end said discharge port (150) and having a profile in which the upper portion (142A) goes nearer to said first wall (141), thus defining an upper region of the hopper, and the lower portion (142B) begins at the minimum distance from said first wall (141) and ends at said discharge port (150) substantially parallel to the extractor belt (160), thus defining a lower region of the hopper, f—said extractor belt (160) has an inclined top surface and g—said port (150) has a cross-section of substantially the same width as the mold (100), so that the flow of the mix (110) is substantially vertical and with a narrowing cross-section in the upper region of the hopper means, while becomes parallel to said top surface of the extractor belt (160) in the lower region of the hopper means and fills the mold (100) without requiring a movement of the hopper means (140) perpendicular to the extractor belt (160).
 2. Distributor according to claim 1, characterized in that a scraper device (180) is present in the proximity of said free end (160A) of the extractor belt (160), for scraping off any residual of mix (110) remaining attached to said extractor belt (160) and a motor-driven brush (185) is present at the other end (160B) of the same extractor belt for completing its cleaning at the end of filling of the mold (100).
 3. Distributor according to claim 1, characterized in that said movable housing (130) and/or said extractor belt (160) are driven by respective variable-speed motors (134, 162) in order to vary the the quantity of mix (110) to be poured into said mold (100) and therefore the thickness of the mix layer filling the mold.
 4. Distributor according to claim 1, characterized in that it said movable housing (130) is mounted on supports (164) provided with load sensors (166) so as to monitor the weight of the mix (110) deposited on said extractor belt (160).
 5. Distributor according to claim 1, characterized in that in front of said discharge port (150) of the hopper means is present a motor-driven comb or rake-like device (170) provided with a plurality of teeth (172) and able to perform an alternating movement on a vertical plane parallel to the cross-section of able to break up any lumps which form in the mix (110) before the latter falls onto the tray-like mold (100).
 6. Distributor according to claim 1, characterized in that it comprises a guide chute (168) positioned at the free end (160A) of said conveyor means (160) and extending transversely over practically the whole width of the mold (100) so as to favor the distribution of the mix (110) therein.
 7. Distributor for filling a tray-like mold (100) with a mix (110) of agglomerated ceramic or stone material having a substantially constant thickness, where said mold (100) is tray-like, made of rubber and used for manufacturing articles in the form of slabs, comprising: a—a fixed structure (120) including a distribution surface (124), where said mold (100) is movably supported, b—a movable housing (130) driven by motor means (134) so as to be displaced above said mold (100) while the mix (110) is distributed over the whole surface thereof, c—hopper means, supported by said movable housing (130) and provided at its bottom end with a port (150) for discharging the mix (110), d—conveyor means integral with said movable housing (130), positioned underneath said hopper means (140) and forming the bottom thereof, which comprise an extractor belt (160) able to receive on its top surface the mix (110) which passes through said discharge port (150) and to convey the mix to its free end (160A) so that the mix falls by effect of gravity and is uniformly poured inside said mold (100), characterized in that e—said discharge port (150) has a cross-section of substantially the same width as the mold (100) and f—a containing frame or border (102) is removably inserted into the mold (100), said frame or border having walls of a height greater than that of the adjacent perimetral edge of the mold (100) so as to prevent the fresh and therefore soft mix (110) from flowing over said edge when it is poured into the mold (100), and inclined towards the interior of the mold to prevent spillage of the mix when said frame (102) is removed from the mold (100).
 8. Distributor according to claim 7, characterized in that said frame (102) is connected to actuating cylinders (126) mounted on said fixed structure (120). 